Qt: Continue using the new window title format.

Update several dialog titles to "Wireshark · <subtile...>".

Change-Id: I64645e913500ecd55a008e1609b46385dafe7de9
Reviewed-on: https://code.wireshark.org/review/6127
Petri-Dish: Gerald Combs <gerald@wireshark.org>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Gerald Combs <gerald@wireshark.org>